# spear-next Project Conversion to Pure Library

## Overview

Converted the `spear-next` project from a hybrid project (library + default binary) to a pure library project by removing the unnecessary `src/main.rs` file. Each required component will have its own independent `main.rs` file.

## Changes Made

### 1. File Deletion
- **Deleted**: `src/main.rs`
  - Reason: No need for default binary entry point
  - Impact: Removed simple "Hello, world!" program

### 2. Cargo.toml Modification
**File**: `spear-next/Cargo.toml`

**Added Configuration**:
```toml
[lib]
name = "spear_next"
path = "src/lib.rs"
```

**Description**:
- Explicitly specify project as library
- Set library entry point to `src/lib.rs`
- Preserve existing `sms` binary target configuration

### 3. tarpaulin.toml Update
**File**: `spear-next/tarpaulin.toml`

**Before**:
```toml
exclude = [
    # Main entry points / 主入口点
    "src/main.rs",
    "src/bin/*",
]
```

**After**:
```toml
exclude = [
    # Binary entry points / 二进制入口点
    "src/bin/*",
]
```

**Description**:
- Removed reference to deleted `src/main.rs`
- Updated comments to reflect current configuration

## Project Structure Changes

### Before
```
spear-next/
├── src/
│   ├── main.rs          # Default binary entry (deleted)
│   ├── lib.rs           # Library entry
│   └── bin/
│       ├── sms/main.rs  # SMS service binary
│       └── spearlet/main.rs # Spearlet binary
└── Cargo.toml
```

### After
```
spear-next/
├── src/
│   ├── lib.rs           # Library entry (main entry point)
│   └── bin/
│       ├── sms/main.rs  # SMS service binary
│       └── spearlet/main.rs # Spearlet binary
└── Cargo.toml
```

## Build Verification

### Library Build
```bash
cargo check --lib
# Success: Generated 20 warnings (unused code), but build successful
```

### Binary Build
```bash
cargo check --bin sms
# Success: SMS binary builds normally
```

## Impact Analysis

### Positive Impact
1. **Clear Project Structure**: Explicitly defined as library project
2. **Component Independence**: Each component has its own binary entry point
3. **Configuration Consistency**: All config files reflect current project structure

### Considerations
1. **Existing Binaries**: `sms` and `spearlet` binaries remain unchanged
2. **Library Functionality**: Project can still be used as library by other projects
3. **Build Warnings**: Unused code warnings exist, can be fixed with `cargo fix`

## Related Files
- `spear-next/Cargo.toml` - Project configuration
- `spear-next/tarpaulin.toml` - Code coverage configuration
- `spear-next/src/lib.rs` - Library entry point
- `spear-next/src/bin/sms/main.rs` - SMS service entry
- `spear-next/src/bin/spearlet/main.rs` - Spearlet entry

## Future Recommendations
1. Run `cargo fix --lib -p spear-next` to fix unused code warnings
2. Add new component binaries to `src/bin/` directory as needed
3. Update project documentation to reflect new project structure